Telegraph system



F; H. HANLEY Jan. 26, 1932.

TELEGRAPH SYSTEM Filed Dec. 24, 1930 mwwawmumm INVENTOR [Jilin/[8y BY Q ATTORNEY Patented Jan. 26, 193.?

UETEO STATES arissa PATET OFF'llil TRAN K H. HANLEY, OF GRANFORID, NEW JERSEY, ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK TELEGRAPH SYSTEM Application filed December 24, 1930.

is essential that the circuits be so arranged that the first opening of the operators key will cause a clean-cut spacing signal to be transmitted to the sending operator, thereby interrupting his sending of signals. When this occurs, there will be no current in the sendin o ierators loo even when his own icy is closed.

The breaking feature of the telegraph sys tem is generally accomplished by a break relay which is equipment furnished in addition to the sending and receiving relays of the telegraph set. This break relay has been found to be undesirable for a number of reasons and this invention has been. made to do away with this additional equipment, i. e., the

1 break relay, and has retained the properties and features of such a relay.

It is in general the ob ect of this invention to provide improved arrangements for th1s purpose by providing at a telegraph station arrangements whereby the armature of the receiving relay is maintained on its marking contact whenever the armature of the sending relay is 011 its spacing contact, thereby rendering the incoming signals to the receiving relay ineifectual to the loop circuit and allowing a spacing signal to be transmitted to the sending operator, which will cause like polarities of battery to be connected to both ends of his loop circuit and will interrupt his sending of signals.

Another of the objects of this invention is to provide a telegraph system which shall accomplish the well known breaking feature with the ordinary sending and receiving re- Serial No. 504,581.

lays of the telegraph set, thereby obviating the necessity for a break relay.

While this invention will be pointed out with particularity in the appended claims, the invention itself, both as to its further objects and features, will be better understood from the detailed description hereinafter following, when read in connection with the accompanying drawing which shows one embodiment of the invention given merely for the purpose of illustration.

Referring to the drawing, the reference character K designates a pair of wires forming a line suitable for receiving carrier waves interrupted in accordance with telegraph sig nals. These currents flow through a receiv ing filter F then through an amplifier A, and become impressed upon the input circuit of a vacuum tube V by means of a transformer T located between the amplifier A and the tube V. It will be apparent that pulses of alternating current corresponding to telegraph signals will appear in the input circuit of the tube V.

The output circuit of the tube V includes the battery B the winding L of a kick transformer T the winding L of a polar receiv ing relay R and the plate and filament electrodes of the tube V and ground. The tube V is employed to act as a rectifier, and by virtue of its rectifying properties the current flowing in its output circuit will be a direct current interrupted in accordance with the telegraph signals. Each pulse of alternating current in the input circuit of the tube V will produce a corresponding direct current pulse in the output circuit of the tube V.

The winding L is the main winding of the receiving relay R This relay also include a kick winding L and a biasing winding L The circuit formed by the winding L will be considered in some detail hereinafter. The winding L is permanently connected in a series circuit which includes a battery 13 a resistance Z the winding L. itself, and ground. Current flows continuously through the latter circuit and the effect produced by winding L, tends to move the armature of the relay R toward its spacing contact S, and if this armature is already on the spacing contact S, the magnetic effect of winding L will tend to hold it on this contact. The magnitude of the biasing effect of winding L is generally about one-half of the magnetic eflect which may be produced by the winding L and moreover, the efiects of windings L and L are mutually opposite.

The armature of relay R is connected to the junction of a pair of resistances designated Z and Z The resistance Z is in series with the winding L of a sending relay R and a loop circuit which includes a key E and a sounder N and a battery 13 as well as ground. The resistance Z is in series with a circuit which includes a winding L of the sending relay R and a variable resistance Z. as Well as ground. The resistance Z, is simply used for balancing purposes. The keyE and the sounder N may be con sidered the equipment at a local station and its circuitis generally known as a loop. The resistance Z is intended to equalize the resistance of the conductors of this loop as well as the-resistance of the sounder N. A longer loop will, of course, require a greater resistance at Z The contacts of the armature of relay R aredesignated M and S and these are generally known as the marking and spacing contacts respectively. These contacts are connected to oppositely poled batteries B. and B both of which are grounded. When the armature of the relay R is in its midposition and free from its contacts M and S and key E is open, no current will flow through the windings L or L of the sending relay R When the contact M of the relay R becomes closed and the key E at the loop is also closed, current will then flow through the winding L of the relay R and its magnitude will be about twice as greatas that flowing through the winding L Since the magnetic effects of windings L and L. are arranged to be mutually opposite and since the magnetic eflect of the winding L is the greater, it will tend to'move the armature of the relay R towards its marking contact M, or to hold it on contact M if it isalready there. When the armature of the relay R closes its spacing contact S, the magnetic effect of the winding L will be reversed, tending to maintain the armature of the relay R closed against its marking contact M.

I l/Vhile this condition exists, the battery 13 which is connected to the spacing contact S of the relay R will oppose the battery B If key E is closed, and since the voltages of these batteries are practically equal 'toeach other,'no current will flow through the wind ing L. If the key E is open, no current will flow through the winding L. of the relay R as was the case when the key E Was closed.

It will be seen that as long as'the key E is open, there will be no magnetic efiect whatever in the winding L of the sending relay R Under this condition the magnetic eiiect of the winding L of the relay R will be dependent upon the position of the armature of the relay R If the armature of the relay R is on its marking contact M, the armature of the relay R will go to its spacing contact However, if the armature of the relay R is on its spacing contact, the armature of the relay R will go to its marking'contact. Thus, whenthe winding L -of the relay R becomes effectively deenergized, the armature of the relay R will close its spacing contact S when the armature of the relay R closesits marking contact, and conversely, the armature of relay R will close its marking contact M-when the armaturesof relay R closes its spacing contact S.

Under these conditions, if a break 'feature, which will be described hereinafter, were not incorporated in the system,.signals received over the circuit K would be retransmitted over the circuit K in reversed form and this would occur for a period oftime which depends upon the length and characteristics of the line circuit.

The armature of the relay R and .its spacing contact S leadto an alternating current generator G which is connected in series with a resistance Z The generator G and its series resistance Z are also connected to a sending filter F which extends to an output circuit K and the circuit K leads to a-distant station. Just as the circuitK receives alternating current signaling pulses from a distant station, so the circuit K sends alternating current signaling pulses to a distant station which may be, and preferably is, the same station'connected or coupled tothe circuit K Thus, it will'be seen that the circuits -K and K form'a four-wire arrangement suitable for thetransmission of pulses ofalternating current in opposite-directions between a-pair of'stations.

it is to benoted' that when the spacing contactS of the relay R is closed byits armature, the generator G will .be short-circuited throughthe resistance Z 'and practically no current will flow from the generator G through the filter F over the'circuit tK Whenthe contact S of the relay R is open, alternating current will be transmitted from generatorG through filter F and over the circuit K Thus, signals composed of pulses ofalternating current may be transmitted over the circuit K in accordance with the operation of the armature of the relay R The armature of the-relay R is grounded.

' The contact M of the relay R is connected 1n series with a resistance Z a battery B and ground. When the armature of the sending relay R is not on its marking contact M, current will flow from batteryB through the winding L 01 the receiving relay R tthe circuit includingbattery B resistance Z ,1the secondary winding -L 'ofthe" kick transformer dli T winding L of relay R and ground. The portion of the latter circuit including the wiiulings L and L will be shunted by the armature of the relay R when this armature closes its marking contact M. Consequently, current will flow from battery 3 through the winding L: of the relay R and this current will be effective in moving the armature of the relay R toward its marking contact M if this armature is not already on this contact, and this will occur only ween the armature of the relay K is not on its maraing contact ll'l.

The operator at the loop may desire to send signals over the circuit K to the distant st tion. This he may do by opening his ltey E in order to gain control of the circuit and break the transmission signals from the distance station over the circuit K the armature of the relay R is on its spacing contact S, the armature of the relay ll, will remain on its marking contact M, and generator will continue to send current through lilter F over the circuit K Still there will be no break in the circuit. When, under the control of incoming signals, the fll'lTlfli'lllE of the relay R goes to its marking contact M, the armature ot' the relay R will reach its spacing contact S and the genera tor G wi l be short-circuited through the re- 1 No current will then be trans muted b the generator G over the circuit F If no break feature were provided and a spacing signal were to be received before the breaking signal had reached the operator at the distant station, the armature of relay K, would be operated to its spacing contact S, thereby caust' g the armature of sending relay ll; to more to its marking contact. This would interrupt the breaking signal.

A special feature of this invention lies in the prevention of the armature of the relay R from leaving its marking contact M after it has reached this contact and after the hey E has been opened by the operator at the loop for the purpose of breaking the circuit. Fliuce the armature ot the sending relay B will tl'iereby be operated to its spacing con tact S, the battery B will supply current through the resistance Z and through the windings L and L and the current through the winding L will of itself be suiiicient to cause the amature of the relay R to close its marking contact M. Contact M of relay R, will remain closed even during the absence of current through winding L of the rel y 3. which, of course, is in the output circuit of the tube V. H, as here shown, the marking contact of the relay B is maintained closed, the spacing contact of the relay R: will also remain closed and no current will flow from the generator Gr over the cir- It is essential to maintain the spaccuit la mg contact of the relay ll closed for a suitiaent interval of time so that the spacing or breaking signal to the distant station located at the distant end oi the circuit K will be completed and registered.

While this invention has been shown and described in certain particular arrangements merely for the purpose of illustration, it will be understood that the general. principles oi this invention may be applied to other and widely varie'd organizations without departing from the spirit of the invention and the scope of the appended claims.

What is claimed is:

1. The combination oi a receiving relay for receiving pulses of direct current corresponding to telegraph signals, a loop including a key, a sending relay connected between the receiving relay and the loop, a circuit con trolled by the armature of the sending relay, and means controlled by the sending relay and responsive to the opening of the key in cluded within the loop to break said circuit and to bring the armatures of the sending and receiving relays into predetermined p sitions and to maintain these armatures in these positions while the key remains open.

2. In a telegraph system, the combination oi a receiving relay having a main winding which may receive signals "Ii-om one line and a kicl: winding, a sending relay which may send gnals over another line, and means to break the ci cuit extending to the sending relay, said breaking means comprising means to transmit current through the kick winding oi the receiving relay to simultaneously hold the armatures of said sending and receiving relays in predetermined positions.

3. The combination of a receiving relay having a first Winding through which direct current pulses will flow and a second winding, a loop, a sending relay interconnecting the armature of the receiving relay with the loop, an alternating current generator con nected between the armature and one of the contacts 01 the sending relay, and a so oi direct current potential which conncc in series with the second winding of the receiving relay, said source of direct current potential. being also connected in series with the armature and the other of the contacts of the sending relay.

l. The combination of a receiving relay having a main winding and an auxiliary winding, a first circuit connected to the re ceiving relay for energizing its main winding with pulses oi. direct current corresponding to signals, a loop, a sen-ding relay interconnecting the armature of the receiving relay with the loop, a second circuit connected between the armature oi the sending relay and one of its contacts, a source of potential controlled by the second circuit, and a, source of direct current potential connected in series with the auxiliary winding of the receiving relay, said source of direct current potential direct current, said receiving being also connected between the armature tion and to maintain'both a'rmaturesin said of the sending relay and its other contact.

5. In a telegraph system, the combination of a receiving relay for receiving relay having a main winding through which said pulses may flow and an auxiliary winding, a sending relay, a source of direct current potential, and a resistance, said source of direct current potential being connected in a permanently closed circuit in series with the auxiliary winding of the receiving relay and with said resistance, the armature and one of the contacts of the sending relay being connected in a circuit in series with the source of direct current potential and the resistance.

6. In a telegraph system having sending and receiving relays, means to break the transmission of signals, said means comprising means to bring the armature of the sending relay into a predetermined position and means responsive to the operation of the armature of said sending relay to bring the armature of the receiving relay into a predetermined position and to maintain the armatures of both relays in these predetermined positions for an appreciable period of time.

7. In a telegraph system having sending and receiving relays suitable for receiving signals from a distant station, means to break the transmission of signals from said distant station, said breaking means comprising electromagnetic means to bring the armature of the sending relay into a predetermined position and electromagnetic means controlled by the armature of the sending relay to bring the armature of the receiving relay into a predetermined position, and means to maintain the armatures of both relays in said positions for an appreciable period of time.

8. Breaking apparatus for a telegraph system having polar sending and receiving relays and a key, comprising means responsive to the opening of said key to bring the armature of the sending relay into a predetermined position, means responsive to the operation oi said sending relay to bring the armature of the receiving relay into a predetermined position, and means to maintain these armatures in said positions until the key subsequentlybecomcs closed.

9. In a telegraph system, the combination of a sending relay, a receivin relay, a loop connected to the sending and receiving relays, a key being included in said loop, and means responsive to the opening of said key to produce a breaking signal, said means comprising means to bring the armature of the sending relay into a predetermined position and means responsive to the operation of said sending relay to bring the armature of the receiving relay into a predetermined posipositions While the keyremains open.

In testimony whereof, I have signed my pulses of name to this specification this 23rd day of December 1930.

FRANK H. HANLEY, 

